1. Field of the Invention
The present invention relates to ink-jet printer units and, more particularly to an ink printing device for multi-colored printing.
2. The Prior Art
A present printing device having a piezoelectrically operated printer head for an ink operated mosaic printing system is disclosed in U.S. Pat. No. 4,158,847. There, an ink printing head is provided with a plurality of printing jets. The jets each lie at the outlet of a delivery channel which is enclosed over a portion thereof by a cylindrical piezoelectric drive element. Upon application of a voltage to the piezoelectric drive elements, a shock wave is generated in the jet channels and ink is injected in droplets from the jet onto a recording medium. Ink flows to the jet channels from a common ink reservoir through a supply line and filters into a common ink distributor mounted adjacent the printing head. Each of the jet channels is connected to the supply of ink in the distributor through a capillary filter device including a throttle plate provided with a number of restricted passages corresponding to the jet channels.
Such printing devices are able to display only a single color, such as black, on a recording medium. However, many instances occur where a multi-colored presentation of characters or graphic patterns is desired. It is possible to range for a plurality of side-by-side printing devices as disclosed in U.S. Pat. No. 4,158,847 to produce a multi-colored presentation on a recording medium. For example, three ink printing heads may be arranged next to one another which discharge droplets in different respective colors, such as magenta, yellow, and blue, and are constructed to apply their ink in succession onto the recording medium. This sort of arrangement would be very cumbersome in a printing operation which includes frequent periods of acceleration and deceleration, as well as requiring about three times more space than a single printer head. Further, the increased expenditure involved in a series arrangement for achieving multi-colored printing is prohibited.